E:\AriUppApps1\ideAris1\main.cpp(26) : error C2662: 'TreeCtrl::Node::SetImage' : cannot convert 'this' pointer from
'const TreeCtrl::Node' to 'TreeCtrl::Node &'
Ah... Well, one of rare cases when C++ does not play well...
Try
TreeCtrl::Node n = tree.GetNode(editid);
n.SetImage(CtrlImg::ImgEdit());
tree.SetNode(editid, n);
Thinking about it, it would probably be better here to return Node value instead of constant reference... what do you think? (Constant reference is faster, however in this case it is very likely you are about to change the value in most cases).